[1] Kenya Govt Med Res Ctr, Ctr Global Hlth Res, POB 1578, Kisumu, Kenya
[2] Stellenbosch Univ, Fac Med & Hlth Sci, Ctr Evidence based Hlth Care, Div Epidemiol & Biostat, Tygerberg, South Africa
[3] Univ Nairobi, Fac Hlth Sci, Dept Pharmacol Clin Pharm & Pharm Practice, Nairobi, Kenya
[4] Univ Liverpool Liverpool Sch Trop Med, Dept Clin Sci, Liverpool, England